1. Field of the Invention
The present invention relates to a liquid crystal display device, particularly to a liquid crystal display device having high definition display and capable of realizing secure ground connection even when used in an environment subject to frequent vibration.
2. Background Art
Conventionally, it has been known that noise generated from the cold cathode tube of a backlight arranged on the backside of a liquid crystal panel adversely affects the display quality of the liquid crystal panel. A technique designed to address this problem has been disclosed in Japanese Patent Laid-Open Publication No. 2001-75485 pertaining to a flat display device, where the member (shield member) having electrical conductivity is arranged around a cold cathode tube, the electrically conductive member being connected to a front frame (bezel cover) to reduce noise.
In addition, Japanese Patent Laid-Open Publication No. 11-183926 pertaining to an attachment structure of foil-state earth wire for a liquid crystal display device, Japanese Patent Laid-Open Publication No. 2001-305971 pertaining to a display device, as well as Japanese Patent Laid-Open Publication No. 2003-15150 pertaining to a liquid crystal panel electrically conductive connection structure, have also been introduced to address such problem. However, the conventional technique is beset with problems.
Specifically, if connection between the shield member and the front frame or the like was in a simple contact state, the connection becomes unstable due to impact or vibration, affecting display quality. Particularly, when the liquid cystal display device is used in an environment subject to frequent vibration or to which impact is easily applied, a joint portion of the device becomes fatigued upon prolonged use depending on the connecting material or connecting mode, resulting in a change in ground pressure change or contact failure.
Further, while the liquid crystal display device has an advantage over the CRT display device because its housing is smaller than that of the latter, problems arise when it is mounted on certain products. For example, the device is required to be as small as possible, keeping the display area fixed and limiting the number of convex portions provided on the housing to as few as possible in order to allow greater freedom in product design.
However, in the technique disclosed in Japanese Patent Laid-Open Publication Nos. 11-183926 and 2001-305971, convex portions are provided on the periphery of the housing and the housing is grounded from a convex portion. Further, while convex portions are not similarly provided in the technique disclosed in Japanese Patent Laid-Open Publication No. 2003-15150, the housing has a special clamped structure, thereby increasing the thickness of the housing. Further, in the technique disclosed in Japanese Patent Laid-Open Publication Nos. 2001-75485 and 2003-15150, a special grounding member is used, which decreases efficiency of the assembly operation, causing increased production cost.